1. Field of the Invention
The present invention relates to a thin-film forming device for forming a thin film, e.g., an insulating film, a metal film, etc., on the surface of a substrate, for example, a semiconductor wafer, for various purposes.
2. Prior Art
There has heretofore been developed a thin-film forming device of the type described above, which has a mechanism for rotating a susceptor having, for example, a semiconductor wafer mounted thereon in a reaction chamber during formation of an insulating film on the semiconductor wafer in order to level the distribution of film thickness on the wafer surface to form an even film. With this thin-film forming device, film growth is carried out with the wafer being rotated at a peripheral velocity higher than the linear velocity of a gas supplied to the reaction chamber, thereby making it possible to form a thin film, e.g., SiO.sub.2, which has a sufficiently uniform film thickness distribution. It has been known that in the above-described thin-film forming system, as the wafer rotating speed is raised, the uniformity of the film thickness improves, and the average film growth rate also increases.
In the above-described conventional thin-film forming device, the rotational speed cannot always be increased as desired because it employs contact type seal mechanism and bearings. Accordingly, it has heretofore been impossible to raise the film growth rate to a satisfactorily high level and to form an even thin film because of the limitation in capability of the device.
In view of the above-described circumstances, it is an object of the present invention to provide a thin-film forming device capable of forming a thin film of uniform thickness on a substrate, a semiconductor wafer, for example, at high speed.